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FIBRE SFP CONNECTIVITY
Optical SFP modules for fibre
connectivity can be used for console
to processing core, router to router,
and router to I/O connections.
Fibre connectivity is required when the
cable run between units exceeds the 90m
maximum permissible length for Cat5e/
Cat6 copper cabling. Fibre can also be
used for shorter runs if it is simply the
preferred medium.
Note that this section only concerns fibre
connections made via SFPs. Like all I/O
boxes, MADI units have pluggable SFPs
for their Hydra2 connections to routers,
but they also have fibre connectors that
pass the actual MADI audio format in and
out of the system. The MADI I/O format
fibre connectors are of a fixed type which
has no relation to SFP choice. Different
build types of MADI I/O box are available
to provide various types of MADI fibre
interface. Please refer to the Hydra2
installation manual for more details on
MADI I/O options.
Singlemodevsmultimode
The core within multimode fibre is
relatively thick when compared to
singlemode. Light travels through
multimode fibre at multiple angles,
'bouncing' of the sides of the core as it
travels through it, taking multiple paths
or 'modes' of varying length from one
end to the other, resulting in pulses being
lengthened as they travel. Singlemode
fibre has a very fine core and light travels
in a single, direct path from one end to
the other without affecting pulse length.
The result is that singlemode fibre
has a higher bandwidth capacity and
importantly, low signal loss allowing much
greater distances to be achieved. Light
can be transmitted into multimode fibre
using LED's or low powered lasers whilst
singlemode requires a higher powered
laser.
46 ARTEMIS
Digital Broadcast Production Console
Calrec recommend the use of singlemode
fibre whenever possible in order to
maximise the flexibility in the location of
hardware and maintain uniformity across
the system by using a single type. If a
multimode infrastructure is in place, fibre
length, the number of inter-connects
and equipment location become more
important.
SFP modules are available for both
singlemode and multimode fibre types.
It is important to select the correct
SFP for the type of fibre being used in
the installation. If using a mixture of
singlemode and multimode fibre, it is
important to ensure the correct SFPs are
matched to the correct fibre type.
Identification
The release button / handles of fibre
SFPs are colour coded - Blue for
singlemode, Black for multimode. Blue
LC connectors, as shown below should be
used to terminate singlemode fibre, and
beige coloured ones for multimode.
DuplexConnectors/terminations
Standard Calrec fibre SFPs, multimode
and singlemode use duplex LC
connectors. The duplex termination
requires two fibres per connection, one
is a send path, the other is a receive path.
When terminating the fibre, the send from
DUPLEX LC FIBRES CORRECTLY TERMINATED A TO B & B TO A
BI-DIRECTIONAL LC FIBRE CORRECTLY CONNECTED, TYPE A TO TYPE B
SFP / FIBRE SPECIFICATIONS
SFP type
Connector Power Budget
SX Multimode
LC Duplex
LX Singlemode
LC Duplex
LX Singlemode bi-di LC Simplex
LH Singlemode
LC Duplex
one end should connect to the receive of
the other and therefore they are 'cross-
over', terminated A to B and B to A.
Singlestrand,bi-directionalSFPs
To reduce the amount of fibre, Calrec
can supply singlemode SFPs that send
and receive over a single, or simplex LC
connector. In order to be able to pass
data in both directions over a single
strand, the light travelling in one direction
needs to be of a different wavelength to
the light travelling in the other direction.
Therefore, bi-directional SFPs come as
either type A, or type B, and they need
to be paired up - A fibre should connect
between a type A and a type B, and not
between two bi-directional SFPs of the
same type / wavelength. The units are
colour coded to aid identification between
type A's & type B's.
SFP/fibrespecifications
Specifications are shown in the table
below. The maximum distances shown
assume a single point to point connection
with no intermediary interconnections.
Losses should be measured across the
total signal path including interconnects
- between points of SFP transceiver
connection. Losses need to be less than
the optical power budget of the SFP
transceivers being used.
Fibre type
62.5/125µm
7.5dB
50/125µm
8dB
8/125µm
11.5dB
9/125µm
23dB
8/125µm
Connection Information
Max Distance
275m
550m
10km
10km
70km
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